Hello All,

I have configured linux sendmail so that it can send mails from the server to the exchange accounts. For this I have edited sendmail.cf file and added the smtp server address in the like :
DSxyz.com

After that I restarted the sendmail server.After this changes i was able to send mails from the server however when I try to reply to these mails they are not getting delivered. Could you please give me any idea what can be the problem.

mailman@dcublrboacms002.blreng.scieng.local on 8/11/2008 2:53 PM
Could not deliver the message in the time limit specified. Please retry or contact your administrator.
< scidubsmtp03.stercomm.com #5.4.7 smtp; 5.4.7 - Delivery expired (message too old) 'DNS Soft Error looking up dcublrboacms002.blreng.scieng.local (MX) while asking iwblrcorsrv004.blreng.scieng.local. Error was: unable to reach nameserver on any valid IP' (delivery attempts: 0)>

From the above msg it looks like to be name resolution error.

Thanks,
Kaps

You need a valid MX record in a valid DNS zone pointing to your server. I really doubt your DNS has a defined zone for "blreng.scieng.local". You cannot just give a machine an arbitrary name and expect that everyone else on the Internet knows what IP address is has from the name. You have to publish it in DNS for that to happen.

The server you are sending to (scidubsmtp03.stercomm.com) is looking up the DNS entry of the server you are sending from (dcublrboacms002.blreng.scieng.local) to see if it's a valid server. The error tells you that the destination server cannot find a DNS server that will respond for the scieng.local domain. To paraphrase "I can't find any server to tell me if the sender is legitimate, and while I was trying, this message got too old to deliver"

You'll have to
1) masquerade the domain in your outgoing mail to something the receiving server can see and verify. How this is done will depend on what MTA you are using.
or....

2) Make the authoritative DNS server for scieng.local visible to stercomm.com

Good Luck!

Dave

Hi Dave,

Thanks for the info however i know that his can be done with masquerade however do u have any steps which I can follow and achieve this?
We are using exchange server.

Thanks,
Kaps

Perhaps you could start by identifying which server is which. There are 3 different server names listed in your error, which one is each of them?

The problem really isn't with the Exchange configuration, it's with the (lack of) configuration on your Linux system. In order to receive mail, it needs to have an MX record in DNS that points to it. There's no indication that you have done this. In fact I stated that in the first response and you seem to have ignored that entirely.

Could you please let me know what things need to be configured on linux system?

You need to explain your environment first. No one is going to be able to give you specific advice without that.

Can I have ur yahoo or gmail id so that I can explain u in detail.

No, you can post it here so everyone can benefit from the knowledge.

What's the hostname of your Sendmail server?
What's the hostname of your Exchange server?
What's the purpose of the third system listed in your original error message?
What is your primary DNS domain.
What's the other domain listed in your original error message?
Who manages the DNS for your domain?
What about the other domain in the error above?